1. Field of the Invention
This invention relates to the seal device for hand pumps dispensing a predetermined quantity of a liquid product, including a product being in atomized or micronized form, or of a paste product contained in bottles or containers.
2. Discussion of the Background
Pumps of this type are well known and comprise essentially a main hollow body of circular cross-section composed of coaxial portions of different diameters and housing all the pump operating members, including a coaxial stem projecting from one of the open ends of the main body. Axially pressing this stem causes delivery of the product contained in the bottle, a certain quantity of air then taking the place of the dispensed product in the bottle.
As is well known, the top of the pump is closed by a plastic annular closure element having a coaxial hole through which the upper part of the pump stem projects to the outside, the hole having a diameter slightly greater than that of the corresponding upper part of the stem. The stem has a coaxial collar, against the lower face of which there rests the upper end of the helical spring of the pump, the upper face of the collar resting under the action of the spring against the lower face of said closure element, along the edge of the hole in this latter.
In known pumps it is usual to provide an annular rubber gasket carried by the collar upper face and disposed between this latter and the lower face of the closure element. This rubber gasket, which provides the seal, has certain drawbacks. In particular, precisely because of the fact that this gasket is of rubber it can alter the product to be dispensed or its smell. In addition, the products to be disposed often contain solvents which tend to dissolve the rubber of said gasket.